Abstract: Safety device for motor vehicles utilizes a cam-like plate and linkage to prevent accidental acceleration of a motor vehicle when disengaging the vehicle's shift lever from the park or neutral position. The apparatus employs an electrical circuit to detect the position of the shift lever and the activation and deactivation of the brake foot pedal. Only after placing the vehicle into any drive position other than park or neutral, and releasing a pedally operated brake pedal, will the linkage permit the throttle of the motor vehicle to move from its idle position to any position selected by the operator upon later application of an operating force to the accelerator pedal. In this manner, the operator is assured that the motor vehicle will not accidentally be caused to lurch forward or backward at high speed.